Identification of cytoskeletal structures in hormone producing lung cancer cell cultures

In order to investigate the intermediate filament protein content of hormone producing lung tumor cell cultures a panel of 16 different cytokeratin antisera were tested using immunocytochemical and biochemical techniques on lung carcinoma cell cultures from different origin. These included three cell cultures derived from small cell lung carcinoma, two large cell carcinoma cell cultures, and two cell cultures derived from squamous cell carcinomas. Flow cytometric analysis of the cell cultures demonstrated that all cell lines examined were aneuploid with DNA-indices ranging from 1.7 to 3.1 rimes the DNA-content of normal human lymphocytes. In both immunofluorescence and immunoperoxidase techniques six out of seven cell cultures reacted with most of the cytokeratin antisera used in a filamentous manner, while a large cell carcinoma cell culture did not react with any of the cytokeratin antisera used. None of the cell cultures examined reacted with the antibodies to neurofilament proteins, suggesting that none of these (neuro)hormone producing cell cultures were of neural origin. All cell cultures which were growing as adherent cell cultures did express vimentin. The cell culture that grew with cells floating in aggregates did not express this intermediate filament protein while a subline which did attach, expressed vimentin. This findings strongly indicates the relation between growth pattern in vitro (floating vs. adherent) and the expression of vimentin. No reaction was found with antisera to desmin and GFAP. The presence of cytokeratins and vimentin in most cell cultures could be confirmed using one- and two-dimensional gel electrophoresis. Cytokeratins 7, 8, 18 and 19 were most commonly present.